when the house lights come up, and everyone is visible, post drinking session, outside of the usual gloom. Where you're just trying to shuffle as quickly as possible to the comfort of the night outside. It's the best.

ones are the ones near the bar and everyone starts downing their pints and people start talking about what time they're up in the morning and you look at your pint and you've only got about an inch of it left and that's it the night is fucking over

The very people you have been hugging all night, become demonic shells of themselves the second the house lights go up. Faces contorting to polar extremes.
That is the time to get the fuck out of there, hopefully having anticipated this and got your shit from the cloakroom already.